With protective coatings, it is possible to reduce corrosion of metalworks, such as bridges, architectural elements and sculptures, by preventing or slowing the passage of water and ions to the metal substrate. Protective coatings may be pigmented; and pigment particles can further slow mass transport of corrosives through films. However, the use of optically transparent coatings is preferable when the ability to see the substrate is a feature for aesthetic and preventative maintenance reasons.
Previous work has shown that polymeric coatings containing polyvinylidene fluoride (PVDF) have longer working lifetimes than polyacrylics and other polymers, due to excellent chemical and thermal stability (Clare et al., Proceedings of Metal 07: Interim Meeting of the ICOM-CC Metal WG Rijksmuseum, Amsterdam, Degrigny, C.; Lang, R. V.; Joosten, I.; Ankersmith, B., Eds. ICOM, 2007: Rijksmuseum, Amsterdam, 2007, 83-87; Iezzi et al., Prog. Org. Coat 2000, 40(1-4):55-60; Wood, Prog. Org. Coat 2014, 77(12)2140-2146; Zhou et al., Adv. Func. Mater. 2013, 23(13):1664-1670). Yet, it has also been shown that water uptake into films produced from waterborne latex coatings is greater than films produced from solvent-based coatings, due to voids in the film caused by defects in spherical close-packing, resulting in a measurable decrease in the films' barrier properties and visible water-whitening of the transparent film (Swartz et al., Prog. Org. Coat. 2012, 75(3):215-223).